This invention relates to ring mechanisms for loose leaf binders with booster or actuating levers which operate both to open and close the binder rings. In the most widely accepted commercial version, such double acting mechanisms have generally involved the use of flat toggle or hinge plates such, for example, as disclosed in U.S. Pat. Nos. 2,061,676 and 3,884,586. In this type of mechanism, an operating lever directly engages the ends of the toggle plates for pivotable movement thereof in opening and closing the rings.
Ring binder mechanisms have also been constructed by attaching the ring segments to parallel rods or wire rails instead of toggle plates as discussed above. In one well-known commerical version of this latter type of ring mechanism, the operating levers or boosters, which engage the rings per se, serve to open the rings only. To close the rings, it is necessary to squeeze the ring halves together manually. This is considered a distinct commercial drawback in comparison with toggle plate type mechanisms, which are readily opened and closed using the booster levers.
In the prior patent art, U.S. Pat. No. 2,013,552 discloses one type of wire rail ring mechanism in which the rings are opened with a lever, but must be closed by hand. U.S. Pat. No. 3,404,685 shows a binder mechanism of the rail type in which the booster levers directly engage the rings per se to open and close the same. In this mechanism, the distance from its fulcrum to the point of engagement with the rings is relatively long. Thus, to provide a suitable mechanical advantage for easy operation, a relatively long lever arm is required. In addition, the lever is pivoted on the fastening rivet for opening the rings and on separate legs to close the rings. This construction is relatively cumbersome and complicated in comparison with the toggle plate type mechanism. Other than the toggle plate type mechanisms, which are invariably pivoted in opposite directions by booster levers, there have heretofore been no known ring mechanisms of the wire rail type wherein the booster levers engage the rails directly the rotate the same in opposite directions.
It is the principal object of the present invention to provide a ring mechanism for loose leaf binders in which the operating rings are carried on wire rails, which are adapted, to be directly rotated in opposite directions by booster levers to both open and close the rings in the manner of a toggle plate mechanism.
It is another object of this invention to provide a ring mechanism of the above type in which the construction of the wire rails are such as to be readily adapted to mass production techniques.
It is a further object of this invention to provide an improved method of manufacturing ring mechanisms of the above type which is simple, efficient and economical.